1. Field of the Invention
The present invention relates to a method of operating a film deposition apparatus and a film deposition apparatus.
2. Description of the Related Art
As methods of film deposition techniques in semiconductor manufacturing processes, a so-called Atomic Layer Deposition (ALD) method is known. In the ALD method, a reaction product is deposited by alternately supplying a plurality of kinds of reaction gasses capable of reacting with each other on a surface of a semiconductor wafer (hereinafter, simply referred to as a “wafer”). In an apparatus to perform the ALD method, a plurality of wafers mounted on a turntable are rotated by the turntable to alternately pass through a plurality of reaction gas supplying areas to which reaction gasses are supplied. In this apparatus, separation areas, to which a separation gas which is an inert gas such as nitrogen gas or the like is provided, are provided between the plurality of the reaction gas supplying areas in a rotation direction of the turntable for preventing mixing of the plurality of reaction gasses (for separating the plurality of reaction gasses). Further, vacuum evacuation ports are provided on a downstream side of the reaction gas supplying areas in the rotation direction of the turntable to evacuate the reaction gasses together with the separation gas.
The plurality of reaction gasses may be, for example, a source gas that is adsorbed on a surface of the wafer and a gas that oxidizes or nitrizes the source gas. Here, when the separation gas is introduced into a source gas supplying area in accordance with the rotation of the turntable, the source gas is diluted by the separation gas to lower the across-the-wafer uniformity in the thickness of a thin film. Thus, in this case, it is necessary to increase the flow rate of the source gas, which causes an increase in cost.
In Patent Document 1, a technique is disclosed in which a flow regulating plate is provided on a gas nozzle extending in a radius direction of a turntable so that the introduction of the separation gas into the source gas supplying area is suppressed and the separation gas tends to flow over the flow regulating plate.
Meanwhile, when performing the film deposition process, a thin film is formed not only on the wafer but also on an upper surface of the turntable. When the thickness of the film formed on the turntable becomes thick after repeating the film deposition process, particles may be generated due to peeling of the film. Thus, it is necessary to periodically remove the thin film formed on the turntable by a cleaning gas.
Here, a position at which a cleaning gas supplying portion is provided may be limited in order to perform a cleaning process while preventing damage to a film deposition apparatus.
For example, wafers are carried in and carried out by an external substrate transferring mechanism at an area (which will be referred to as a “passing area”) in the film deposition apparatus. Generally, a monitor for monitoring the passing of the wafers is provided at the passing area. Thus, in order to prevent deterioration of the monitor by the cleaning gas, it is better to provide the cleaning gas supplying portion apart from the passing area. Therefore, a layout may be considered in which the cleaning gas supplying portion is positioned in the vicinity of the source gas supplying area, which is apart from the passing area. However, as described above, if a flow regulating plate is provided on a gas nozzle, the cleaning gas may flow over the flow regulating plate, similarly as the separation gas, so that the amount of the cleaning gas that contacts the turntable is reduced. This increases cleaning time.
Thus, it is necessary to direct gas flow in order to effectively perform the cleaning process on the turntable.